From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 3 Sep 2001 04:41:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 3 Sep 2001 04:40:59 -0400 Received: from ns.suse.de ([213.95.15.193]:10506 "HELO Cantor.suse.de") by vger.kernel.org with SMTP id ; Mon, 3 Sep 2001 04:40:48 -0400 Date: Mon, 3 Sep 2001 10:41:05 +0200 From: Andi Kleen To: "David S. Miller" Cc: ak@suse.de, alan@lxorguk.ukuu.org.uk, willy@debian.org, thunder7@xs4all.nl, parisc-linux@lists.parisc-linux.org, linux-kernel@vger.kernel.org Subject: Re: [parisc-linux] documented Oops running big-endian reiserfs on parisc architecture Message-ID: <20010903104105.A3398@gruyere.muc.suse.de> In-Reply-To: <20010903002514.X5126@parcelfarce.linux.theplanet.co.uk.suse.lists.linux.kernel> <20010903.011530.62340995.davem@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <20010903.011530.62340995.davem@redhat.com>; from davem@redhat.com on Mon, Sep 03, 2001 at 01:15:30AM -0700 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 03, 2001 at 01:15:30AM -0700, David S. Miller wrote: > From: Andi Kleen > Date: 03 Sep 2001 09:29:12 +0200 > > And also everybody connected to the internet needs them, because you can > create arbitarily unaligned TCP/UDP/ICMP headers using IP option byte sized > NOPs. > > IP header length is measured in octets, so how is this possible? > :-) Sorry that came out wrong. You can in theory generate unaligned IP options this way, but the kernel handles this correctly using memcpy. What it doesn't handle is unaligned TCP options (e.g. timestamps); which you can create using TCP option byte fillers. Also the 4 byte alignment of the header doesn't help much when the driver didn't cooperate. -Andi